Fluids for Extreme Pressure and Wear Applications

ABSTRACT

Provided are compositions, additives for forming compositions, methods of operating apparatus in fluid communication with the compositions, and apparatus comprising the compositions. For example, the composition may include a polyalphaolefin component of from about 95% to about 99.5% w/w. The composition may include an additive component. The additive component may include an anti-wear agent. The anti-wear agent may be from about 0.1% to about 2% w/w. The anti-wear component may be characterized by an acid value of at least about 1 mg KOH/g. The additive component may include an aryl amine antioxidant agent, an anti-rust agent, and a metal deactivator agent. The composition may be characterized by a kinematic viscosity at 100° C. of at least about 5 centiStokes, a viscosity index of at least about 80, and an acid value in mg KOH/g of between about 0.1 and about 1.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part application of U.S. patentapplication Ser. No. 15/137,799, filed Apr. 25, 2016, which is acontinuation application of U.S. patent application Ser. No. 13/848,227,filed Mar. 21, 2013, now U.S. Pat. No. 9,321,980, which is acontinuation application of U.S. patent application Ser. No. 12/924,984,filed Oct. 8, 2010, now abandoned. Each of the preceding applications isentirely incorporated herein by reference.

GOVERNMENT SUPPORT

This invention was made with government support under contract no.N00024-05-C-4169 awarded by the Department of Defense. The governmentmay have certain rights in the invention.

FIELD OF THE INVENTION

Provided are lubricant and functional fluids suitable for high-stressapplications.

BACKGROUND

Lubricants and functional fluids used in submarine propulsion systemsmay encounter challenging operating conditions in terms of pressure,wear, service life, and the like. Submarines may function independentlysuch that their operating systems may need to perform reliably over longtime periods. If a problem occurs with a submarine at sea, the chancesfor outside assistance may be remote. It is desirable that a lubricatingfluid in a submarine be reliable, and, due to space and weightrestraints, be multifunctional.

The current lubricating oil used in U.S. Navy submarines (known as2190-TEP) is a mineral oil based fluid that meets the militaryspecification MIL-PRF-17331. This oil has been used in submarines forthe past forty years, but the U.S. Navy has increased the severity ofthe operating conditions in its fleet. For example, compared to pastsystems, the U.S. Navy now has faster new drive systems that have muchhigher gear-to-fluid volume interactions, operating under higheroperating temperatures, which leads to more thermal efficiency. The netresult of these more stressful operating conditions is that the existing2190-TEP fluid is failing more quickly leading to high oil replacementand high disposal costs.

Problems observed in conjunction with these more stressful operatingconditions include (a) high depletion of antioxidants in the mineral oilbased 2190-TEP fluid, (b) sharp increases in total acid number and (c)severe off-gassing events. Degradation leads to the formation ofcomponents such as formaldehyde and carbon monoxide that can beparticularly hazardous in the close operating conditions of thesubmarine.

The present application appreciates that providing fluid compositions,for example, to provide lubrication or other functions in high stressoperating conditions, such as U.S. navy submarines, may be a challengingendeavor.

SUMMARY OF THE INVENTION

In one embodiment, a composition is provided. The composition mayinclude a polyalphaolefin component in a percentage, w/w of thecomposition, of from about 95% to about 99.5%. The composition mayinclude an additive component. The additive component may include ananti-wear agent. The anti-wear agent may be, in a percentage, w/w of thecomposition, of from about 0.1% to about 2%. The anti-wear component maybe characterized by an acid value of at least about 1 mg KOH/g. Theadditive component may include an aryl amine antioxidant agent. Theadditive component may include an anti-rust agent. The additivecomponent may include a metal deactivator agent. The composition may becharacterized by a kinematic viscosity at 100° C. of at least about 5centiStokes. The composition may be characterized by a viscosity indexof at least about 80. The composition may be characterized by an acidvalue in mg KOH/g of between about 0.1 and about 1.

In another embodiment, an additive composition for a lubricant orfunctional fluid is provided. The additive composition may include ananti-wear agent in a percentage, w/w of the additive composition, offrom about 10% to about 30%. The anti-wear component may becharacterized by an acid value of at least about 1 mg KOH/g. Theadditive composition may include an aryl amine antioxidant agent, in apercentage, w/w of the additive composition, of from about 10% to about30%. The additive composition may include an aryl amine antioxidantagent, in a percentage, w/w of the additive composition, of from about10% to about 30%. The additive composition may include an alkyl oralkenyl succinic acid ester anti-rust agent. The additive compositionmay include a tolyl triazole derivative metal deactivator agent.

In one embodiment, a method of operating an apparatus using acomposition is provided. The method may include placing a plurality ofcomponents of the apparatus in fluid communication with the composition.The composition may be a fluid. The composition may include apolyalphaolefin component in a percentage, w/w of the composition, offrom about 95% to about 99.5%. The composition may include an additivecomponent. The additive component may include an anti-wear agent. Theanti-wear agent may be, in a percentage, w/w of the composition, of fromabout 0.1% to about 2%. The anti-wear component may be characterized byan acid value of at least about 1 mg KOH/g. The additive component mayinclude an aryl amine antioxidant agent. The additive component mayinclude an anti-rust agent. The additive component may include a metaldeactivator agent. The composition may be characterized by a kinematicviscosity at 100° C. of at least about 5 centiStokes. The compositionmay be characterized by a viscosity index of at least about 80. Thecomposition may be characterized by an acid value in mg KOH/g of betweenabout 0.1 and about 1.

In another embodiment, an apparatus including a composition is provided.A plurality of components of the apparatus may be in fluid communicationwith the composition. The composition may be a fluid. The compositionmay include a polyalphaolefin component in a percentage, w/w of thecomposition, of from about 95% to about 99.5%. The composition mayinclude an additive component. The additive component may include ananti-wear agent. The anti-wear agent may be, in a percentage, w/w of thecomposition, of from about 0.1% to about 2%. The anti-wear component maybe characterized by an acid value of at least about 1 mg KOH/g. Theadditive component may include an aryl amine antioxidant agent. Theadditive component may include an anti-rust agent. The additivecomponent may include a metal deactivator agent. The composition may becharacterized by a kinematic viscosity at 100° C. of at least about 5centiStokes. The composition may be characterized by a viscosity indexof at least about 80. The composition may be characterized by an acidvalue in mg KOH/g of between about 0.1 and about 1.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C include depictions of an apparatus used in a wear test usedto validate results obtained in accordance with an example embodiment;

FIG. 1A is an illustration of a specimen configuration;

FIG. 1B is an illustration of a gear material;

FIG. 1C is an illustration of specimen processing;

FIG. 2 is a graph of the parameters of the results obtained in a highspeed load capacity test, validating the beneficial characteristicsobtained in accordance with an example embodiment;

FIG. 3 is a table that describes, in part, various example formulationsof the composition;

FIG. 4 is a table that describes, in part, various example formulationsof the composition;

FIG. 5 is a table that describes, in part, various example formulationsof the composition; and

FIG. 6 is a table that describes, in part, various example formulationsof the composition.

DETAILED DESCRIPTION

Various embodiments of the invention described herein may address theshortcomings of the prior art.

The more rigorous performance conditions demanded by newer ships may behandled by lubricating using the fluid composition of the presentinvention. In addition to submarines, newer surface ships withcontrollable pitch propeller systems have placed additional demands onthe existing 2190-TEP lubricant. The improved properties of the presentinvention may also find advantageous use in place of existing hydraulicfluids, air compressor fluids and reducing gear fluids. Anotheradvantage of the present invention is that a single formulation may beproduced, stored and sourced for a variety of uses, which may beespecially beneficial while at sea. Accordingly, applications for thepresent invention include lubricating and hydraulic oil, and otherfunctional fluids for motion control, steam turbines and gears in shipsand submarines, as submarine air compressor lubricating oil, and incontrollable pitch propeller systems in ships and submarines. Ofparticular interest in many military applications are new lubricants orfunctional fluids that are able to provide both corrosion resistance andlubricating properties. Until now no synthetic lubricant composition hasmet certain stringent military requirements such as those in U.S.military specification MIL-PRF-17331 for both lubricating andanticorrosive properties.

In addition, lubricant or functional fluid additive packages andlubricants and functional fluids of the present invention may findadditional commercial applications in lubricating environments involvingdesired low turnover and/or high gear-to-fluid volume interactions, suchas may be found, for instance in wind turbine gear systems. Many of theissues faced in submarines are also presented in wind turbines, where itmay be desirable to operate over long operating time intervals in remotelocations, and with substantial effort and expense associated withlubricant change-over.

The invention includes, inter alia, an additive package, a lubricant orfunctional fluid including the additive package, apparatus containingthe lubricant or functional fluid, and methods of operating apparatususing the lubricant or functional fluid.

In various embodiments, a composition is provided. The composition mayinclude a polyalphaolefin component in a percentage, w/w of thecomposition, of from about 95% to about 99.5%. The composition mayinclude an additive component. The additive component may include ananti-wear agent. The anti-wear agent may be, in a percentage, w/w of thecomposition, of from about 0.1% to about 2%. The anti-wear component maybe characterized by an acid value of at least about 1 mg KOH/g. Theadditive component may include an aryl amine antioxidant agent. Theadditive component may include an anti-rust agent. The additivecomponent may include a metal deactivator agent. The composition may becharacterized by a kinematic viscosity at 100° C. of at least about 5centiStokes. The composition may be characterized by a viscosity indexof at least about 80. The composition may be characterized by an acidvalue in mg KOH/g of between about 0.1 and about 1.

In some embodiments, the polyalphaolefin component may be, in apercentage, w/w of the composition, of one of about 95, 95.5, 96, 96.5,97, 97.5, 98, 98.5, 99, or 99.5, or a range between any two of thepreceding values, for example, from about 95% to about 99.5%. Thepolyalphaolefin component may be any polyalphaolefin component, or ablend thereof, such as commercially available polyalphaolefincompositions and blends. Examples of commercially availablepolyalphaolefin compositions are typically sold according to nominalkinematic viscosity at 100° C. in centiStokes, e.g., SYNTON® PAO 40(Chemtura Corporation, Middlebury, Conn.) has a kinematic viscosity at100° C. of 40 centiStokes; SynBase Polyolefin 40 (Solitex, Inc.,Houston, Tex.) has a kinematic viscosity at 100° C. of 41-43centiStokes; SYNFLUID® PAO 40 (Chevron Phillips Chemical Company LP, TheWoodlands, Tex.) has a kinematic viscosity at 100° C. of 39 centiStokes;and the like. In various embodiments of the composition, thepolyalphaolefin component may include any such component or blendthereof with desired kinematic viscosity. For example, the kinematicviscosity of the composition at 100° C. in centiStokes may be about, orat least about, one or more of: 10, 10.25, 10.5, 10.75, 11, 11.25, 11.5,11.75, 12, 12.25, 12.5, 12.75, 13, 13.5, 14, 14.5, 15, 17.5,20, 25, 30,35, 40, 45, 50, 75, or 100, or a range between any two of the precedingvalues, for example, between about 10 and about 100. In variousembodiments, the kinematic viscosity may be determined at least in partby the polyalphaolefin component. The desired kinematic viscosity of thefluid composition may be approximately selected by mixing variousamounts of commercially available polyalphaolefin fractions. FIGS. 3-6are tables that show various fluid compositions in which differentamounts of PAO fractions at various kinematic viscosities at 100° C. maybe combined to arrive at a fluid composition having a correspondingoverall kinematic viscosity.

In some embodiments, the viscosity index of the fluid composition may beabout, or at least about, one or more of 80, 85, 90, 94, 95, 100, 105,110, 115, 120, 125, 130, 135, 137, 140, 150, 175, 200, 250, 300, 350, or400, or a range between any two of the preceding values, for example,between about 80 and 400. The viscosity index may be determinedaccording to that described for synthetic fluids in ASTM D4638 (AmericanSociety for Testing Materials, West Conshohocken, Pa.).

In several embodiments, the fluid composition may include the additivein a percentage, w/w of the composition, of one or more of about: 0.5,1, 1.5, 2, 2.5, 3, 3.5, 4. 4.5, or 5, or a range between any two of thepreceding values, for example, between about 0.5% and about 5%. Thefluid composition may consist essentially of the polyalphaolefincomponent and the additive. The fluid composition may consist of thepolyalphaolefin component and the additive.

In various embodiments, the anti-wear agent may be present, in apercentage, w/w of the composition, of one of about 0.1, 0.2, 0.3, 0.4,0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1,1.15, 1.2, 1.25, 1.5, 1.75, or 2, or a range between any two of thepreceding values, for example, of from about 0.1% to about 2%,

In some embodiments, the anti-wear agent may include one or more of: analkylated triarylphosphate, e.g., alkylated with one or more C₃-C₆ alkylgroups, such as isopropylated triaryl phosphate, tert-butylated triarylphosphate, and the like; an alkyl phosphate, e.g., with a C₄-C₁₈ alkylgroup, such as octyl phosphate, decyl phosphate, dodecyl phosphate,tetradecyl phosphate, hexadecyl phosphate, combinations thereof, and thelike; a diarylether phosphate ester; a diarylether phosphate diesterdiphosphate; combinations thereof; and the like. For example, theanti-wear agent may include one or more of: a C₃-C₆ alkylatedtriarylphosphate, a C₄-C₁₈ alkyl phosphate, a diarylether phosphateester and a diarylether phosphate diester diphosphate.

In several embodiments, esters in the anti-wear agent may be partlyesterified, e.g., partly esterified dodecyl phosphate, such that theanti-wear agent may be characterized by an acid value, e.g., accordingto D974 (American Society for Testing Materials, West Conshohocken,Pa.). For example, the anti-wear agent may be characterized by an acidvalue in mg KOH/g of one of about 1, 2.5, 5, 7.5, 10, 11, 12, 13, 14,15, 17.5, 20, 22.5, 25, 27.5, 30, 35, 40, 45, 50, 75, 100, 125, 150,175, or 200, or a range between any two of the preceding values, forexample, of from about 1 to about 200. The amount of the anti-wear agentin the composition may be selected in view of the acid value of theanti-wear agent to provide the acid value described for the compositionherein. For example, the total acid value of the fluid composition in mgKOH/g may be about: 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7. 0.8, 0.9, or 1,or a range between any two of the preceding values, for example, betweenabout 0.1 mg KOH/g and about 1 mg KOH/g.

In various embodiments, suitable anti-wear agents may be obtained orrequested according to the above characteristics from commercial sourcesof anti-wear agents, for example, DURAD® 310M, a mixture ofisopropylated triphenyl phosphate and partially esterified C₈-C₁₆phosphates (reaction products of a mixture of C₈-C₁₆ alcohols withphosphorus oxide), having a nominal acid value of 13 mg KOH/g(CHEMPOINT®, Bellevue, Wash.); certain REOLUBE® series phosphate esteradditives (Canoil Canada Ltd., Mississauga, Ontario Calif.); certainFRYQUEL® series phosphate ester additives (ICL Industrial Products,Gallipolis Ferry, W. Va.); certain ADDITIN® series phosphate esteradditives (Rhein Chemie Holland line, LANXESS Corporation, Pittsburgh,Pa.; certain Lubrizol products (Lubrizol Corporation, Wickliffe, Ohio);and the like. Suitable anti-wear agents may include or be obtained asdescribed elsewhere herein.

In some embodiments, suitable antioxidants may include aryl amineantioxidants, for example, phenyl alpha naphthyl amines (PAN) andalkylated phenyl alpha naphthyl amines (APAN), e.g., NAUGALUBE® seriesPAN/APAN antioxidants (CHEMPOINT®, Bellevue, Wash.). Suitableantioxidants may include or be obtained as described elsewhere herein.The anti-oxidant may be present, in a percentage, w/w of thecomposition, of one of about 0.1, 0.2, 0.3, 0.4, 0.5, 0.55, 0.6, 0.65,0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.5,1.75, or 2, or a range between any two of the preceding values, forexample, of from about 0.1% to about 2%,

In several embodiments, suitable anti-rust agents may include, in someembodiments, the anti-wear agent itself. Suitable anti-rust agents mayinclude, in some embodiments, alkyl succinic acid esters, alkenylsuccinic acid esters, and the like, e.g. derivatives such as ADDITIN® RC4801, (Rhein Chemie Holland line, LANXESS Corporation, Pittsburgh, Pa.Suitable anti-rust agents may include or be obtained as describedelsewhere herein. The anti-rust agent may be present, in a percentage,w/w of the composition, of one of about 0.025, 0.045, 0.05, 0.055,0.075, 0.100, 0.125, or 0.150, or a range between any two of thepreceding values, for example, of from about 0.025% to about 0.15%,

In various embodiments, suitable metal deactivator agents may include,for example, triazoles, e.g., tolyl triazole derivatives such asADDITIN® RC 8239, (Rhein Chemie Holland line, LANXESS Corporation,Pittsburgh, Pa.). Suitable metal deactivator agents may include or beobtained as described elsewhere herein. The metal deactivator may bepresent, in a percentage, w/w of the composition, of one of about 0.025,0.045, 0.05, 0.055, 0.075, 0.100, 0.125, or 0.150, or a range betweenany two of the preceding values, for example, of from about 0.025% toabout 0.15%,

In some embodiments, the aryl amine antioxidant may include one or moreof: a phenyl alpha naphthyl amine and an alkylated phenyl alpha naphthylamine. The anti-rust agent may include an alkyl or alkenyl succinic acidester. The metal deactivator agent may include a tolyl triazolederivative.

In various embodiments, the anti-wear agent and the aryl amineantioxidant may be present in the composition in independently selectedamounts. The anti-rust agent and the aryl amine antioxidant agent may bepresent in substantially equal amounts. The anti-rust agent and themetal deactivator agent may be present in the composition inindependently selected amounts. The anti-rust agent and the metaldeactivator agent may be present in substantially equal amounts.

In several embodiments, the composition may be characterized by akinematic viscosity at 100° C. in centiStokes of between about 10 andabout 20; a viscosity index of between about 150 and about 250; and anacid value in mg KOH/g of between about 0.2 and about 0.6. See, forexample, the various example formulations in FIG. 3. The composition maybe characterized by a kinematic viscosity at 100° C. in centiStokes ofbetween about 5 and about 8; a viscosity index of between about 100 andabout 225; and an acid value in mg KOH/g of between about 0.2 and about0.6. See, for example, the various example formulations in FIG. 4. Thecomposition may be characterized by a kinematic viscosity at 100° C. incentiStokes of between about 8 and about 10; a viscosity index ofbetween about 150 and about 250; and an acid value in mg KOH/g ofbetween about 0.2 and about 0.6. See, for example, the various exampleformulations in FIG. 5. The composition may be characterized by akinematic viscosity at 100° C. in centiStokes of between about 10 andabout 13; a viscosity index of between about 150 and about 250; and anacid value in mg KOH/g of between about 0.2 and about 0.6. See, forexample, the various example formulations in FIG. 6.

In some embodiments, the composition may be characterized upon testingunder ASTM D4638 for 72 h at 175° C. by a decrease in acid value. Thedecrease in acid value may be, for example, a percentage of about one ormore of 5, 10, 20, 30, 40, 45, 50, 55, 60, 70, or 80, or a range betweenany two of the preceding values, e.g., a decrease of between about 5%and about 80%. The composition may be characterized upon testing underASTM D4638 for 72 h at 175° C. by an increase in kinematic viscosity,e.g., at 100° C. The increase in kinematic viscosity may be, forexample, a percentage of about one or more of 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 20, or 30, or a range between any two of the preceding values, e.g.,an increase of between about 1% and about 30%.

In various embodiments, the composition may be characterized by aWedeven Associates Machine load stage failure test rating value (WAMvalue) of about the same or greater compared to a WAM value measuredunder the same test conditions for at least one of: 2190-TEP; a firsttest formulation of the composition in which the anti-wear agent isreplaced by a low acid number anti-wear agent characterized by an acidvalue of less than 1 mg KOH/g; a second test formulation of thecomposition in which the anti-wear agent substantially comprises amethylated triarylphosphate; a third test formulation of the compositionthat substantially excludes a partly esterified phosphate ester; afourth test formulation of the composition that substantially excludesthe aryl amine antioxidant; and a fifth test formulation of thecomposition that substantially excludes an alkyl or alkenyl succinicacid ester.

In several embodiments, the composition may be characterized by arotating bomb oxidation test value (RBOT value, ASTM D2272) of about thesame or greater compared to a RBOT value measured under the same testconditions for at least one of: 2190-TEP; a first test formulation ofthe composition in which the anti-wear agent is replaced by a low acidnumber anti-wear agent characterized by an acid value of less than 1 mgKOH/g; a second test formulation of the composition in which theanti-wear agent substantially comprises a methylated triarylphosphate; athird test formulation of the composition that substantially excludes apartly esterified phosphate ester; a fourth test formulation of thecomposition that substantially excludes the aryl amine antioxidant; anda fifth test formulation of the composition that substantially excludesan alkyl or alkenyl succinic acid ester.

In various embodiments, an additive composition for a lubricant orfunctional fluid is provided. The additive composition may include anyaspect of the additive component described herein. For example, theadditive composition may include an anti-wear agent in a percentage, w/wof the additive composition, of from about 10% to about 30%. Theanti-wear component may be characterized by an acid value of at leastabout 1 mg KOH/g. The additive composition may include an aryl amineantioxidant agent, in a percentage, w/w of the additive composition, offrom about 10% to about 30%. The additive composition may include anaryl amine antioxidant agent, in a percentage, w/w of the additivecomposition, of from about 10% to about 30%. The additive compositionmay include an alkyl or alkenyl succinic acid ester anti-rust agent. Theadditive composition may include a tolyl triazole derivative metaldeactivator agent.

In one embodiment, a method of operating an apparatus using acomposition is provided. The method may include placing a plurality ofcomponents of the apparatus in fluid communication with the composition.The composition may be a fluid. The composition may include apolyalphaolefin component in a percentage, w/w of the composition, offrom about 95% to about 99.5%. The composition may include an additivecomponent. The additive component may include an anti-wear agent. Theanti-wear agent may be, in a percentage, w/w of the composition, of fromabout 0.1% to about 2%. The anti-wear component may be characterized byan acid value of at least about 1 mg KOH/g. The additive component mayinclude an aryl amine antioxidant agent. The additive component mayinclude an anti-rust agent. The additive component may include a metaldeactivator agent. The composition may be characterized by a kinematicviscosity at 100° C. of at least about 5 centiStokes. The compositionmay be characterized by a viscosity index of at least about 80. Thecomposition may be characterized by an acid value in mg KOH/g of betweenabout 0.1 and about 1.

In several embodiments, the method may include any aspect of thecomposition as described herein. For example, the method may include,upon operating the apparatus with the fluid composition, causing in thefluid composition one or more of: a decrease in acid value; and anincrease in viscosity.

The plurality of components of the apparatus may include, for example,one or more of: a hydraulic line, a hydraulic reservoir, a piston, agear surface, a bearing surface, a cam surface, a compressor, a blade, arotatable shaft, a propeller pitch controller, and a turbine. Theapparatus may be included, for example, by a submarine, a ship, or awindmill.

In another embodiment, an apparatus including a composition is provided.A plurality of components of the apparatus may be in fluid communicationwith the composition. The composition may be a fluid. The compositionmay include a polyalphaolefin component in a percentage, w/w of thecomposition, of from about 95% to about 99.5%. The composition mayinclude an additive component. The additive component may include ananti-wear agent. The anti-wear agent may be, in a percentage, w/w of thecomposition, of from about 0.1% to about 2%. The anti-wear component maybe characterized by an acid value of at least about 1 mg KOH/g. Theadditive component may include an aryl amine antioxidant agent. Theadditive component may include an anti-rust agent. The additivecomponent may include a metal deactivator agent. The composition may becharacterized by a kinematic viscosity at 100° C. of at least about 5centiStokes. The composition may be characterized by a viscosity indexof at least about 80. The composition may be characterized by an acidvalue in mg KOH/g of between about 0.1 and about 1. The plurality ofcomponents of the apparatus may include, for example, one or more of: ahydraulic line, a hydraulic reservoir, a piston, a gear surface, abearing surface, a cam surface, a compressor, a blade, a rotatableshaft, a propeller pitch controller, and a turbine. The apparatus may beincluded, for example, by a submarine, a ship, or a windmill.

Lubricant or Functional Fluid Additive

In some embodiments, the lubricant or functional fluid additive of theinvention may be described as a lubricant or functional fluid additivefor a polyolefin oil blend, including a mixture of: (a) an anti-wearcomponent consisting essentially of 95% isopropylated triarylphosphate,which has the following general chemical structure:

and 5% dodecyl phosphate, which has the following general chemicalstructure:

the dodecyl phosphate being only partially esterified, the anti-wearcomponent present in the polyolefin oil blend in a range of from about0.75 percent to about 2.00 percent by weight; (b) an antioxidantcomponent selected from the group consisting of alkylatedphenyl-alpha-naphthylamine (“APAN”), phenyl-alpha-naphthylamine (“PAN”)and mixtures thereof, and present in the polyolefin oil blend in a rangeof from about 0.75 percent to about 2.00 percent by weight; (c) ananti-rust component including an alkylated succinic acid ester anti-rustagent, and present in the polyolefin oil blend in a range of from about0.025 percent to about 0.075 percent by weight; and (d) a metaldeactivator component including a tolytriazole derivative, which has thefollowing general chemical structure:

and present in the polyolefin oil blend in a range of from about 0.025percent to about 0.075 percent by weight.

The antioxidant component may be present in the polyolefin oil blend ina range of from about 1.00 percent to about 2.00 percent by weight. Theanti-wear component may be, may consist essentially of, or may consistof Durad 310M.

The anti-wear component may be present in the polyolefin oil blend in arange of from about 1.00 percent to about 2.00 percent by weight. Theantioxidant component may be, may consist essentially of, or may consistof NAUGALUBE® APAN or PAN, which has the following general chemicalstructure:

In this same regard, it was found that, where the anti-wear componentconsists essentially of APAN and/or PAN, or consists of APAN and/or PAN,the most improved anti-oxidative performance was achieved.

The anti-rust component may be present in the polyolefin oil blend in arange of from about 0.045 percent to about 0.055 percent by weight. Theanti-rust component may be, may consist essentially of, or may consistof LZ-859, which has the following general chemical structure:

The metal deactivator component may be present in the polyolefin oilblend in a range of from about 0.045 percent to about 0.055 percent byweight. The metal deactivator component may be, may consist essentiallyof, or may consist of Irgamet 39.

The lubricant additive for a polyolefin oil blend may include a mixtureof: (a) an anti-wear component that may be, may consist essentially of,or may consist of 95% isopropylated triarylphosphate and 5% dodecylphosphate, the dodecyl phosphate being only partially esterified, theanti-wear component present in the polyolefin oil blend in a range offrom about 1.00 percent to about 2.00 percent by weight; (b) anantioxidant component selected from the group consisting of alkylatedphenyl-alpha-naphthylamine, phenyl-alpha-naphthylamine and mixturesthereof, and present in the polyolefin oil blend in a range of fromabout 1.00 percent to about 2.00 percent by weight; (c) an anti-rustcomponent including an alkylated succinic acid ester anti-rust agent,and present in the polyolefin oil blend in a range of from about 0.045percent to about 0.055 percent by weight; and (d) a metal deactivatorcomponent including a tolytriazole derivative, and present in thepolyolefin oil blend in a range of from about 0.045 percent to about0.055 percent by weight.

Lubricant/Functional Fluid Composition

The lubricant/functional fluid composition of the present invention maybe of a lubricating viscosity and may include: (a) a polyalphaolefinhaving a viscosity of about 10 centiStokes at 100° C. and present in thelubricant or functional fluid composition in a range of from about 84percent to about 88 percent by weight; (b) a polyalphaolefin having aviscosity of about 40 centiStokes at 100° C. and present in thelubricant or functional fluid composition in a range of from about 11percent to about 13 percent by weight; (c) an anti-wear component thatmay be, may consist essentially of, or may consist of 95% isopropylatedtriarylphosphate and 5% dodecyl phosphate, the dodecyl phosphate beingonly partially esterified, the anti-wear component present in thepolyolefin oil blend in a range of from about 0.75 percent to about 2.00percent by weight; (d) an antioxidant component selected from the groupconsisting of alkylated phenyl-alpha-naphthylamine,phenyl-alpha-naphthylamine and mixtures thereof, and present in thepolyolefin oil blend in a range of from about 0.75 percent to about 2.00percent by weight; (e) an anti-rust component including an alkylatedsuccinic acid ester anti-rust agent, and present in the polyolefin oilblend in a range of from about 0.025 percent to about 0.075 percent byweight; and (f) a metal deactivator component including a tolytriazolederivative, and present in the polyolefin oil blend in a range of fromabout 0.025 percent to about 0.075 percent by weight.

The polyalphaolefin characterized by a viscosity of about 10 centiStokesat 100° C. may be present in the lubricant or functional fluidcomposition in an amount of about 86 percent by weight. Thepolyalphaolefin characterized by a viscosity of about 40 centiStokes at100° C. may be present in the lubricant or functional fluid compositionin an amount of about 12 percent by weight.

The various parameters of the additive package may be as set forthabove.

The fluids of the present invention optionally may include one or moredyes, such as Unisol Liquid Red BHF, or Silicone Oil(polydimethlysiloxane), such as Dow Corning 200, which has the followinggeneral chemical structure:

The fluid composition may include:

PAO 10 85.8 PAO 40 12.0 Durad 310M 1.0 NAUGALUBE ® APAN 1.0 LZ-859 0.10Irgamet 39 0.10 Unisol Liquid Red BHF 0.010 Dow Corning 200 0.002

The fluid of the present invention may find uses in any applicationrequiring high performance, with the advantages of stable storage anduse in environments that may have to accommodate low lubricant orfunctional fluid turnover. Examples may include marine and submarineuse, as well as lubrication and functional fluid applications in windturbines and the like.

EXAMPLES Example 1

The following technical reports describe the development of theantioxidant as well as a brief chronological summary of the 2190-S fluiddevelopment.

The research was designed to develop a synthetic alternative to Navy2190-TEP. A series of synthetic basestocks and mixtures were evaluated,such as polyalphaolefins, alkylated naphthalenes, diesters, polyolesters and polyalkylene glycols, all containing a common commerciallyavailable additive package. Lubrizol 857 additive was used, which isrecommended at a treat level of 1.4-3.0% in petroleum basestocks to meetthe requirements of Navy's MIL-PRF-17331 specification. The researchidentified 3 candidate fluids that looked promising in most regards,with the exception of rust protection.

Further research focused on improving the rust protection of thecandidate formulations. The Lubrizol 857 package was recommended for useat 1.4-3.0%, and was applied initially at a level of 1.5%. Increasingthe concentration of the LZ 857 to 3.0-5.0% improved the rustprotection, but it was found to be insoluble in the PAO basestock atconcentrations above 2.0%. One of the major components of LZ-857 istricresyl phosphate (TCP) antiwear (AW) additive. Solubility experimentsshowed that TCP has poor solubility in PAO.

It became apparent that there was still a need to improve the solubilityof the antiwear additive in PAO. Chemtura of Middlebury, CT manufacturesTCP under the trade name Durad 125. The Durad product line includes anumber of other alkylated triarylphosphate esters with larger alkylgroups on the triarylphosphate. Durad 300 is an isopropylatedtriarylphosphate and Durad 620B is a t-butylated triaryphosphate. It wasfound that substituting the methyl groups on TCP with isopropyl ort-butyl groups greatly improved the PAO solubility of these AWadditives.

It was further determined to examine other components of the additivepackage to see what other attributes of the finished fluid could beimproved by reformulation of the additive. The second major component ofthe Lubrizol 857 additive package is the antioxidant (AO). Most of theAO development effort was conducted over a period of several months. Itwas during this period that PAN and APAN were identified as desirable AOperformers and BC-1 as a desirable finished fluid formulation.

A foaming test indicated that the BC-1 formula benefited from anantifoam (AF) additive to meet the specification requirements, so apolydimethylsoloxane, Dow Corning 200, was added, with the new formulabeing called BC-1A. BC-1A remained a desirable candidate for two yearsuntil evaluated against the existing 2190-TEP fluid in an FZG gearlubrication test. Although BC-1A met the MIL-PRF-17331 specificationgear test requirement, it did not perform as well as 2190-TEP.

It was determined to adjust the formulation again by modifying the DuradAW additive. Durad 310M is a mixture of 95% Durad 300 isopropylatedtriarylphosphate and 5% dodecyl phosphate. The dodecyl phosphate is onlypartially esterified, leaving some free acid phosphate present that isbelieved to be more reactive towards active sites on a steel gearsurface. The free acid phosphate is believed to act as a trigger toinitiate the formation of an iron phosphate lubricating film at theasperity contacts of the rubbing steel surfaces. A test method wasneeded to optimize the AW characteristics and gear lubricationproperties of the formulation.

The US Navy has used the Ryder Gear Test as a means of evaluatingaviation gas turbine engine oils. While it has enjoyed a successfulhistory, it also has some drawbacks as a test. A few years ago, the Navyfunded Wedeven Associates to develop an alternative test to simulate thespeeds, loads and sliding forces experienced by gear teeth. See FIG. 1.The Wedeven Associates Machine (WAM) utilizes a steel ball rotating on arotating disc, each of which are driven independently, allowing for arange of motion from full rolling motion to full sliding motion. Todemonstrate the invention, 7-8 different formulations were prepared withvarying concentrations of Durad 620B and Durad 310M. The WAM testresults showed a level of 1% Durad 310M provided the most cost effectivemeans of achieving the same AW characteristics and gear lubricationproperties as the existing 2190-TEP fluid. This formulation is referredto as BC-1A-5 and is the current 2190-S formula.

One effective embodiment of the fluid composition includes:

PAO 10 85.8 PAO 40 12.0 Durad 310M 1.0 NAUGALUBE ® APAN 1.0 LZ-859 0.10Irgamet 39 0.10 Unisol Liquid Red BHF 0.010 Dow Corning 200 0.002

Example 2 Antioxidant Evaluation

The effectiveness of various antioxidants in the synthetic fluid wasevaluated using differential scanning calorimetry (DSC) in accordancewith the ASTM D6186 method to measure the oxidation induction time ofthe fluid formulations. Initially the formulations were tested underconditions of atmospheric pressure and 200° C. Later the test conditionswere modified by decreasing the temperature to 180 and increasingpressure to 500 PSI. An iron catalyst was also added to promoteoxidation.

In both sets of tests, formulation BC-7 containingphenylalphanaphthylamine (PAN) and BC-1 containing alkylatedphenylalphanaphthylamine (APAN) proved to offer superior oxidationresistance.

These results demonstrate the unanticipated results obtained with thethe present invention with respect to the antioxidant performance, ascompared to other formulations outside the scope of the presentinvention.

Example 3 Lubrication Evaluation

Rapid and fairly economical tribological test methods that may simulatethe sliding friction and forces of gear teeth, such as those developedby Wedeven Associates, use a WAM ball-on-disk machine as shown inFIG. 1. Both the ball and disk are made of AISI 9310 steel typicallyused for gear applications, and are independently driven so theirrotational speeds and contact load can be controlled. The test wasactually developed with funding from NAVAIR in an effort to develop analternative to their Ryder Gear Test Method that has been routinely usedto evaluate aviation gearbox and gas turbine engine oils. Thelubrication characteristics of the 2190-S fluid were optimized throughsubjecting a series of formulations for WAM Load Capacity testing.

Originally, samples of Navy 2190-TEP and the current 2190-S (labeledBC-1A) were tested, along with two additional formulations BC-1A-2 andBC-1A-3. The formulation designated 2190-S (BC-1A) contained 1% Durad620B anti-wear additive. BC-1A-2 contained 2% of Durad 620B and BC-1A-3contained 1.5% Durad 620B and 0.5% Durad 310M. Navy 2190-TEP exhibited aWAM Load Stage Failure of 24, while the BC-1A, BC-1A-2 and BC-1A-3 gaveload stage failures of 14, 18 and 23 respectively.

Based on these results, it became clear that the Durad 310M was a muchmore effective load carrying additive than Durad 620B. In order tooptimize the formulation for cost and performance, three more fluidswere prepared. BC-1A-4 contained 0.5% each of 620B and 310M, BC-1A-5contained 1.0% 310M alone, and BC-1A-6 contained 1.0% each of 620B and310M. These fluids produced load stage failures of 23, 26 and 26respectively. BC-1A-5 is considered to be the optimum formulationbecause it provides the highest load capacity at the lowest anti-wearadditive treat level. Fluid formulations and corresponding WAM loadstage failure loads are listed in Table 2.

Durad 620B and 310M are similar compounds with important differences.Both are alkylated triphenyl phosphates, but the alkyl groups on the620B are butyl groups, while those on 310M are isopropyl groups. Moreimportantly, the 310M contains 5% of an alkyl acid phosphate, whichgives the 310M and acid value of 10-15 mg KOH/g versus an acid value of0.1 maximum for 620B. The free acid phosphate has a strong affinity formetal surfaces and forms lubricious surface films more readily than theneutral acid phosphate.

FIG. 2 is a graph of the parameters of the results obtained in a highspeed load capacity test, validating the beneficial characteristicsobtained in accordance with one embodiment of the present invention.

These results further demonstrate the unanticipated results obtainedwith the present invention with respect to the further anti-wear packageperformance, in addition to the results obtained with respect to theantioxidant performance described above as compared to otherformulations outside the scope of the present invention.

Example 4 The Fluid Composition Surprisingly Decreases in Acid Value andIncreases in Viscosity under Oxidation and Corrosion Stability Testing

One significant problem observed in conjunction with the more stressfuloperating conditions used in current U.S. Navy submarine applications isthat the prior art mineral oil based 2190-TEP fluid displays a sharpincreases in total acid number under operating condition stresses. Theincreased acidity of the 2190-TEP fluid increases wear on parts anddecreases the hydrolytic and oxidative stability of the fluid. Thus, thesharp increase in acid number indicates a corresponding decrease inlubricant properties and fluid lifetime, followed by increased wear andcorrosion damage to the components in contact with the fluid.

A series of samples of the fluid composition were submitted to anoxidation and corrosion stability test according to ASTM D4638 (AmericanSociety for Testing Materials, West Conshohocken, Pa.). For example, asample of 2190-S was prepared meeting the constituent amounts describedfor BC-1A-5 in Table 2. The sample had an initial viscosity of 87.11centiStokes at 40° C. per ASTM D445) and 12.34 centiStokes at 100° C.per ASTM D445) and an acid value of 0.41 mg KOH/g (per ASTM D664). Thesample was exposed to oxidation and corrosion stability conditionsaccording to ASTM D4638 for 72 h at 175° C. Surprisingly andunexpectedly, the acid value decreased by over 46%, to 0.22 mg KOH/g,while the viscosity increased by 5.5%, to 91.90 centiStokes (at 40° C.).The decrease in acid value and increase in viscosity under oxidation andcorrosion stability testing is surprisingly and unexpectedly contrary tothat observed for the prior art mineral oil based 2190-TEP fluid and lowacid number fluids such as BC-1A in Table 2. Moreover, the decrease inacid value and increase in viscosity under oxidation and corrosionstability testing is indicative of surprisingly and unexpectedly higherfluid stability and better preservation of lubricant and other fluidproperties, which corresponds to better performance and better componentprotection.

The instant invention is shown and described herein in what isconsidered to be the most practical and preferred embodiments. It isrecognized, however, that departures may be made therefrom which arewithin the scope of the invention, and that obvious modifications willoccur to one skilled in the art upon reading this disclosure.

What is claimed is:
 1. A composition, comprising: a polyalphaolefincomponent in a percentage, w/w of the composition, of from about 95% toabout 99.5%; and an additive component, comprising: an anti-wear agentin a percentage, w/w of the composition, of from about 0.1% to about 2%,the anti-wear component characterized by an acid value of at least about1 mg KOH/g; an aryl amine antioxidant agent; an anti-rust agent; and ametal deactivator agent; the composition being characterized by: akinematic viscosity at 100° C. of at least about 5 centiStokes; aviscosity index of at least about 80; and an acid value in mg KOH/g ofbetween about 0.1 and about
 1. 2. The composition of claim 1, comprisingthe additive component, in a percentage, w/w of the composition, of fromabout 0.5% to about 5%.
 3. The composition of claim 1, the anti-wearagent comprising a partly esterified phosphate ester.
 4. The compositionof claim 1, the anti-wear agent comprising one or more of: a C₃-C₆alkylated triarylphosphate, a C₄-C₁₈ alkyl phosphate, a diaryletherphosphate ester and a diarylether phosphate diester diphosphate.
 5. Thecomposition of claim 1, comprising the aryl amine antioxidant in apercentage, w/w of the composition, of from about 0.1% to about 2%. 6.The composition of claim 1, one or more of: the aryl amine antioxidantcomprising one or more of: a phenyl alpha naphthyl amine and analkylated phenyl alpha naphthyl amine; the anti-rust agent comprising analkyl or alkenyl succinic acid ester; and the metal deactivator agentcomprising a tolyl triazole derivative.
 7. The composition of claim 1,the anti-rust agent comprising an alkyl or alkenyl succinic acid ester,the anti-rust agent and the metal deactivator agent each beingindependently present in a percentage, w/w of the composition, of fromabout 0.025% to about 0.15%.
 8. The composition of claim 1,characterized by one of: (a) a kinematic viscosity at 100° C. incentiStokes of between about 10 and about 20; a viscosity index ofbetween about 150 and about 250; and an acid value in mg KOH/g ofbetween about 0.2 and about 0.6; (b) a kinematic viscosity at 100° C. incentiStokes of between about 5 and about 8; a viscosity index of betweenabout 100 and about 225; and an acid value in mg KOH/g of between about0.2 and about 0.6; (c) a kinematic viscosity at 100° C. in centiStokesof between about 8 and about 10; a viscosity index of between about 150and about 250; and an acid value in mg KOH/g of between about 0.2 andabout 0.6; and (d) a kinematic viscosity at 100° C. in centiStokes ofbetween about 10 and about 13; a viscosity index of between about 150and about 250; and an acid value in mg KOH/g of between about 0.2 andabout 0.6.
 9. The composition of claim 1, the composition characterizedupon testing under ASTM D4638 for 72 h at 175° C., by at least one of: adecrease in acid value; and an increase in viscosity.
 10. Thecomposition of claim 1, characterized by a Wedeven Associates Machineload stage failure test rating value (WAM value) of about the same orgreater compared to a WAM value measured under the same test conditionsfor at least one of: 2190-TEP; a first test formulation of thecomposition in which the anti-wear agent is replaced by a low acidnumber anti-wear agent characterized by an acid value of less than 1 mgKOH/g; a second test formulation of the composition in which theanti-wear agent substantially comprises a methylated triarylphosphate; athird test formulation of the composition that substantially excludes apartly esterified phosphate ester; a fourth test formulation of thecomposition that substantially excludes the aryl amine antioxidant; anda fifth test formulation of the composition that substantially excludesan alkyl or alkenyl succinic acid ester.
 11. The composition of claim 1,characterized by a rotating bomb oxidation test value (RBOT value) ofabout the same or greater compared to a RBOT value measured under thesame test conditions for at least one of: 2190-TEP; a first testformulation of the composition in which the anti-wear agent is replacedby a low acid number anti-wear agent characterized by an acid value ofless than 1 mg KOH/g; a second test formulation of the composition inwhich the anti-wear agent substantially comprises a methylatedtriarylphosphate; a third test formulation of the composition thatsubstantially excludes a partly esterified phosphate ester; a fourthtest formulation of the composition that substantially excludes the arylamine antioxidant; and a fifth test formulation of the composition thatsubstantially excludes an alkyl or alkenyl succinic acid ester.
 12. Anadditive composition for a lubricant or functional fluid, comprising: ananti-wear agent in a percentage, w/w of the additive composition, offrom about 10% to about 30%, the anti-wear component characterized by anacid value of at least about 1 mg KOH/g; an aryl amine antioxidantagent, in a percentage, w/w of the additive composition, of from about10% to about 30%; an aryl amine antioxidant agent, in a percentage, w/wof the additive composition, of from about 10% to about 30%; an alkyl oralkenyl succinic acid ester anti-rust agent; and a tolyl triazolederivative metal deactivator agent.
 13. The additive composition ofclaim 14, the anti-wear agent comprising a partly esterified phosphateester.
 14. The additive composition of claim 14, the anti-wear agentcomprising one or more of: a C₃-C₆ alkylated triarylphosphate, a C₄-C₁₈alkyl phosphate, a diarylether phosphate ester and a diaryletherphosphate diester diphosphate.
 15. The additive composition of claim 14,characterized by the anti-rust agent and the aryl amine antioxidantagent being present in substantially equal amounts.
 16. The additivecomposition of claim 14, characterized by the anti-wear agent and themetal deactivator agent being present in substantially equal amounts.17. The composition of claim 1, the aryl amine antioxidant comprisingone or more of: a phenyl alpha naphthyl amine and an alkylated phenylalpha naphthyl amine.
 18. A method of operating an apparatus using afluid composition, comprising placing a plurality of components of theapparatus in fluid communication with the fluid composition, the fluidcomposition comprising: a polyalphaolefin component in a percentage, w/wof the composition, of from about 95% to about 99.5%; and an additivecomponent, comprising: an anti-wear agent in a percentage, w/w of thecomposition, of from about 0.1% to about 2%, the anti-wear componentcharacterized by an acid value of at least about 1 mg KOH/g; an arylamine antioxidant agent; an anti-rust agent; and a metal deactivatoragent; the composition being characterized by: a kinematic viscosity at100° C. of at least about 5 centiStokes; a viscosity index of at leastabout 80; and an acid value in mg KOH/g of between about 0.1 andabout
 1. 19. The method of claim 18, comprising upon operating theapparatus with the fluid composition, causing in the fluid compositionone or more of: a decrease in acid value; and an increase in viscosity.20. The method of claim 18, the apparatus comprised by a submarine, aship, or a windmill.